Since this is used only in idetape_blkdev_ioctl(), remove the typedef and make
the struct function-local.

Bart:
- s/sizeof(struct idetape_config)/sizeof(config)/
Signed-off-by: NBorislav Petkov <bbpetkov@yahoo.de>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>